/*
 *
 *  * Copyright (c) [2019-2021] [NorthLan](lan6995@gmail.com)
 *  *
 *  * Licensed under the Apache License, Version 2.0 (the "License");
 *  * you may not use this file except in compliance with the License.
 *  * You may obtain a copy of the License at
 *  *
 *  *     http://www.apache.org/licenses/LICENSE-2.0
 *  *
 *  * Unless required by applicable law or agreed to in writing, software
 *  * distributed under the License is distributed on an "AS IS" BASIS,
 *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  * See the License for the specific language governing permissions and
 *  * limitations under the License.
 *
 */

package org.lan.iti.iha.security.matcher;

import javax.servlet.http.HttpServletRequest;
import java.util.Collections;
import java.util.Map;

/**
 * Simple strategy to match an <tt>HttpServletRequest</tt>.
 *
 * @author NorthLan
 * @date 2021/7/30
 * @url https://blog.noahlan.com
 */
public interface RequestMatcher {

    /**
     * Decides whether the rule implemented by the strategy matches the supplied request.
     *
     * @param request the request to check for a match
     * @return true if the request matches, false otherwise
     */
    boolean matches(HttpServletRequest request);

    /**
     * Returns a MatchResult for this RequestMatcher The default implementation returns
     * {@link Collections#emptyMap()} when {@link MatchResult#getVariables()} is invoked.
     *
     * @return the MatchResult from comparing this RequestMatcher against the
     * HttpServletRequest
     * @since 5.2
     */
    default MatchResult matcher(HttpServletRequest request) {
        boolean match = matches(request);
        return new MatchResult(match, Collections.emptyMap());
    }

    /**
     * The result of matching against an HttpServletRequest Contains the status, true or
     * false, of the match and if present, any variables extracted from the match
     *
     * @since 5.2
     */
    class MatchResult {

        private final boolean match;

        private final Map<String, String> variables;

        MatchResult(boolean match, Map<String, String> variables) {
            this.match = match;
            this.variables = variables;
        }

        /**
         * @return true if the comparison against the HttpServletRequest produced a
         * successful match
         */
        public boolean isMatch() {
            return this.match;
        }

        /**
         * Returns the extracted variable values where the key is the variable name and
         * the value is the variable value
         *
         * @return a map containing key-value pairs representing extracted variable names
         * and variable values
         */
        public Map<String, String> getVariables() {
            return this.variables;
        }

        /**
         * Creates an instance of {@link MatchResult} that is a match with no variables
         *
         * @return
         */
        public static MatchResult match() {
            return new MatchResult(true, Collections.emptyMap());
        }

        /**
         * Creates an instance of {@link MatchResult} that is a match with the specified
         * variables
         *
         * @param variables
         * @return
         */
        public static MatchResult match(Map<String, String> variables) {
            return new MatchResult(true, variables);
        }

        /**
         * Creates an instance of {@link MatchResult} that is not a match.
         *
         * @return
         */
        public static MatchResult notMatch() {
            return new MatchResult(false, Collections.emptyMap());
        }

    }
}
